A variety of substance handling devices have been proposed assisting in procedures for performing chemical, biological, biochemical, physical analysis and the like, of substances, including the performance of assays such as, for example, Enzyme-Linked Immunosorbent Assay (ELISA). These substance handling devices are usually adapted to securely hold the substance, thereby enabling the transportation of the substance(s) of interest, and may come in the form of a plate that is provided with a binding coating, or which comprises one or more wells, like for example, a capillary channel system or a microtiter plate. As outlined herein below in greater detail, substance handling devices may also be implemented as pipettes.
U.S. Patent Application Publication No. 2003/119030 to Zilber, entitled “Immunoassay Diagnostic Probe and a Method for Use Thereof”, discloses a disposable probe for the quantitative detection of specific biomolecules, being the analyte, in a fluid sample, by any known immunoassay procedure which is based on spectroscopic detection. The probe of comprises at least one photodiode chip having a layer of first immunoreactant molecules attached permanently to its surface, said first immunoreactant binds specifically to the analyte, and the photodiode has electronic connectors for transferring the electronic signal generated in the photodiode, upon exposure to light, to a signal processing unit. According to the present invention, part or all of the signal processing components, such as amplifier, A/D converter, etc., can be packaged together with the photodiode in a single semiconductor chip (a photo-sensor chip).
U.S. Pat. No. 6,197,494 to Oberhardt, entitled “Apparatus for Performing Assays on Liquid Samples Accurately, Rapidly and Simply”, discloses a device which comprises a channel structure defining a sample well and a reaction volume in communication with each other. The channel structure posses a geometry which causes a liquid sample placed into the sample well to be drawn into and fill the reaction volume via capillary action, wherein after the reaction volume is filled, the liquid sample remains stationary.
Referring now in greater detail to pipettes, the latter are devices used in a laboratory environment for the transport of a measured volume of fluids, for example, from and to vials, troughs and microtiter plates having different numbers of wells (e.g., 96, 384 and 1536) for the analysis of physical, biological, biochemical or chemical reactions. More specifically, the pipette is operative to dispense, and optionally draw, an adjustable amount of fluid from and into a pipette tip, respectively. The volume of fluid that is transportable by pipette tips ranges from microliters to milliliters. Such fluids encompass liquids which may include, for example, samples and reagents.
Pipette tips are commonly made out of polypropylene (PP) and glass. Less common materials are polytetrafluoroethylene, polysulfone, polyethersulfone, polyethylene, fluoropolymers, cellulose acetate, polystyrene, polystyrene/acrylonitrile copolymer, and Polyvinylidene Fluoride (PVDF).
In correspondence with the variety of applications in which pipette tips can be employed, they come in different designs. Accordingly, the length, diameter, and the shape of pipette tips can vary. Pipette tips can for example have a cylindrical or a conical shape. Moreover, different mechanisms are used for drawing and dispensing fluid into and from the pipette tip. These mechanisms include, for example, piston-driven displacement pipettes, positive displacement pipettes and vacuum assisted pipettes. Pipette tips may include external and internal coatings resulting in, for example, conductive, hydrophilic or hydrophobic surfaces by coating the surface. Furthermore, pipette tips may be filled with various compounds such as coated beads, gels such as Thermo Scientific Proxeon. The usage of pipette tips filled with compounds may not be limited to the transport of fluid but also to additional applications such as, for example, filtration and/or purification.
Further developments of pipettes relate to the capability of performing analysis of the level of the fluid in the pipette tip, as outlined herein below.
U.S. Patent Application Publication No. 2010/0288058 to Laiho, entitled “Pipette Body, Pipette Tip and Method” discloses a pipette tip wherein the tip body is provided with a first optical grating structure arranged to conduct light away from the tip body to the side of the inner surface thereof. The tip body is provided with a receiving grating structure arranged to receive the light conducted away from the tip body through the first optical grating structure. A first end of the tip body has means for fastening the pipette tip to the pipette body, and a light-receiving surface optically connected through the tip body to the first optical grating structure. Furthermore, the first end comprises a surface that conducts light away and is optically connected through the tip body to the receiving optical grating structure. Light generating means and means for directing the light to the pipette tip body are arranged in the pipette body.
It will be appreciated that for simplicity and clarity of illustration, elements shown in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference numerals may be repeated among the figures to indicate identical and analogous elements but may not be referenced in the description for all figures.